Since the advent of fuel injection systems, it has become almost universal to utilize electric fuel pumps to furnish fuel to internal combustion engines of automotive vehicles. This system has supplanted the old system of drawing fuel from a tank with a vacuum system or a fuel pump driven in the engine compartment. However, since the fuel tank is usually mounted at the rear of a vehicle below the rear passenger compartment it has become an objective to minimize, as much as possible, the noise and vibration resulting from the rotating, positive-displacement pumps often used for this purpose. This effort has resulted in pump design to reduce flashback noise. It has also resulted in efforts to mount the pump in such a way as to isolate noise and vibration.
In some instances a canister, that is, a small container is mounted in a fuel tank to receive fuel return from a pressure regulator in the pumping circuit or from an aspirator system. In this arrangement the pump is mounted in the canister, usually parallel to the axis of the canister, and draws fuel from the bottom of the canister to deliver to an outlet conduit leading to the engine fuel supply. One example of a noise reduction structure is found in a U.S. Pat. No. to Tuckey, 4,780,063 (1988) where a ribbed pliable jacket is used to surround and mount the pump. Another example is illustrated in the above-referenced copending application of Hoover and Talaski, Ser. No. 284,996, filed Dec. 16, 1988, where metal coil springs mount a pump housing within a jacket which is supported on a fuel return pipe projection within a fuel tank. This return pipe can be in a fuel tank canister or the pump may be mounted in a baffle system in the tank, or in the tank itself.
The present invention has also the objective of noise and vibration reduction with a specially designed grommet at each end of a surrounding jacket, the jacket being mounted to a flange within the tank, or to a baffle, or to a return pipe extending into a fuel tank or a canister. The grommet has radial projections which contact, respectively, the surrounding jacket and the pump housing itself. The contact, support, and isolation projections and the grommet walls on which the projections are mounted are resilient to absorb longitudinal and lateral pump vibrations as well as torsional pump vibrations to eliminate transmission to the enclosing canister or fuel tanks.
Objects and features of the invention will be apparent in the following specification and claims in which the principles of the invention are set forth together with details to enable persons skilled in the art to practice the invention, all in connection with the best mode presently contemplated for the invention.